Poly (ether sulfone) is a special engineering plastic with exceptional comprehensive physical properties. Due to its comprehensive heat resistance (heat distortion temperature 200-220° C.), hydrolysis resistance (withstanding 150-160° C. hot water or vapor), creep resistance, dimensional stability, impact resistance, chemical resistance, non-toxicity, flame retardance, etc., it has been widely applied to such fields as electrics, electronics, machinery, automobile, hot water, medical apparatus and food processing. Its global production capacity has reached tens of thousands of tons, represented by Solvay Chemicals, Inc. However, over long-term application and extension, higher heat resistance requirements are being raised in different fields of application. In other words, there is a prevalent expectation for increasing its heat resistance grade from today's H to C while keeping its mechanical properties unchanged. It is driven by this market demand that we have completed the study of copolymers containing the diphenyl sulfone ether structure with a higher heat resistance grade, and created this patent on the basis of existing polysulfone patents, such as ZL200510017259.8, by first synthesizing monomers containing the diphenyl sulfone structure successfully using the principle of molecular design and ternary polymerization technology.